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Blunders at East Devon

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This long collection is the result of computer-searching a
database of games from the East Devon Congress this year (1999). I
had 222 games to analyse, courtesy of Ian George who had the
thankless task of bashing them all in: 111 from the Major section
(U155), and 111 from the Premier (U205). Of these, exactly half
were identified by Fritz 5 as having tactical blunders (see
Appendix for notes on how this was done). The 111 blunders
comprised 65 from the Major and 44 from the Premier.

If you would like to repeat the exercise for yourself, you can
download the games from the Premier (CBH or PGN) and Major (CBH or
PGN) and compare your computer's efforts to the results of my
analysis (CBH or PGN).

Having had the games marked by Fritz, I then went through the
games to decide which were real blunders and which were Fritz
getting its wires crossed (see appendix). The resulting list of
blunders I then inspected and tried to identify (a) what tactical
device was at work, and (b) if there were typical errors of
thinking going on. Here's an example:

Fritz assesses White's position at the end of the analysis
variation as +?.?. When you dump the database out for printing, it
unhelpfully strips all these assessments off, but they can be seen
in the CBH database.

Psychologically, this is a missed opportunity. It is also a
threat missed by Black, so both players made a mistake. Tactically,
it's a decoy/overload combination, and two moves deep. I'm sure
that Black overlooked the possibility of Rxe5, and missed it
because it was a second effect of moving the White Queen from e2 to
f1, defending against the mate on g2. My guess is that Brian also
overlooked the possibility, rather than saw it and thought it a bad
idea. Of course, I actually don't know enough about any of these
games to be able to tell things like this for sure. Either player
may have seen all this and more, although this begs the question
why they didn't react to what they saw.

Three features dogged my research: these difficulties in
post hoc interpretation, compounded by lack of context,
and possible transcription errors. On context: some of the games I
witnessed and was able to tell that one or other player was in time
trouble, when some of the decisions taken might make a bit more
sense. Or a player may have grabbed a draw against a higher-graded
opponent. Also, I assume that the scores are accurate. Ian did
mighty battle with idiosyncratic handwriting and moves scribbled in
time pressure, but there are a couple of games where I can only
assume some other move was played than the one recorded. (I once
found a score sheet which started: 1. e4 e5 2. Nc6 Nc6 3.
Nf6 Nf6 - a player new to algebraic, I concluded.)

What I have done below is a preliminary description of the
blunders - a natural history, if you like, trying to classify and
count my way through the range of horrors on view. The richness of
chess - even this sort of chess - really requires deeper
consideration than I have been able to give it so far, so please
forgive this as work in progress.

One obvious theme is a move of the opponent with two points, one
of which you miss.

Another is mood: a player ahead on material or with a strong
attack may overlook opportunities for the defending side. Or a
player who is being attacked may panic and find it difficult to
focus on simple threats of the opponent, or become gloomy and stop
looking.

White overlooks a tactic made possible by Black overlooking the
threat - so every missed opportunity may also represent an error of
the opponent, allowing you to carry out a threat that could have
been prevented.

16.Nxd5 back on track
16...exd5 ? Unnecessary! White must have some idea
in mind, and there's no need here to fall for it.

[2.81 : 16...Qxc2 17.Nxf6+ Nxf6 18.Bd3 Qc7 19.Qe5 Nd5 20.Qxc7
Nxc7]

17.Qxd5+ Kh8 18.Qxa8

That opportunity was only taken because it was re-presented.

After this, I suspect we are at the limit of what many players
can analyse accurately without mistakes. Given a favourable wind,
we might follow a given sequence some ten moves deep, but not
reliably identifying or analysing all the alternative branches.
Still, see if you can do better than the tournament winner
here:

17.Nxd5 is the most obvious line to analyse, and it is not bad
for Black: 17...Nxd5 18.exd5 Bxg5 19.Qg3 Bxd5 20.Qxg5]

I put this one under 'analysis' rather than the similar example
above which was 'bluffed'; this one is a short line which I guess
White failed to analyse, the one above was a long line which I'm
sure Black looked at but feared ending badly.

The phrase 'bad moves in bad positions' is from Hugh Alexander.
Partly this is statistical: when you stand worse, fewer of your
moves will not lead to trouble. One can have sympathy. But it is
also psychological: panic, depression or a general lowering of
expectations can all cause decision-making and chosen moves to
become poorer. I saw loads of these...

(5) Ingham W. - Pinder R. [A07] East Devon Major 1999
(1)

This was almost as common as the 'bad to worse' pattern: not
really being in top gear when looking at a favourable position.
There are many factors at play here: nerves, complacency, laziness
and more.

Time control here was at move 40, so any game which degenerates
around move 35 or even earlier could be due to clock pressure. Time
trouble doesn't provide a complete explanation for out-and-out
blunders, but it does produce them. We saw one I guess in
Evans-Dunn.

I analysed all the games using the 'blundercheck' feature of
Fritz 5. I used the default settings of time 10, (seconds I think)
and a criterion of 60 (a difference of more than half a Pawn
[100]). Left to run overnight, Fritz identifies better lines and
flags each game containing a blunder with a black spot, which it
describes as a "medal". These settings seem to result in a depth of
about depth of 10-ply (5 whole moves by White and Black).

I assume these defaults are generally OK, but I don't know if
anyone has found a better combination of settings.

Fritz takes the instruction to look for only ten seconds very
seriously. That is, Fritz is capable of assessing a position after
Black's fifth move as favourable to Black, even if White's sixth
move delivers checkmate!

Proof: in this position...

(72) Bolt G. - Talbot A. R. [B86]

East Devon Premier 1999 (2)

...Black came up with a creative way to lose a piece, which
Fritz assessed at +3.22 for White:

32...Qxh3 33.gxh3 Nf3 34.Qxe3 Nxe1 35.Qxe1

Fritz preferred the move:

32...Rge8 when it analysed: 33.Rhxe3 Rxe3 34.Qxe3 Nxb3 35.Qxb3
Rxd6 36.Re8+ Kh7 37.Qxb7, after which 10 ply it assessed the
position as only 0.81 to White - how would you assess it?

So, a "blunder" in Fritz' terms (a better move was available
with an outcome a Pawn's worth different), but in practical terms,
who cares? Incisiveness in critical positions is important, but
this finale was hardly critical. Some of the 111 games with
blunders were like this one. Meanwhile the phase of the game where
Black failed to castle, got in a horrid pin and shed all his
Queen's-side Pawns and a piece, is passed over in silence.

Fritz, like many computers, likes the bird in the hand more than
many players. Undoubtedly, if it did not have an opening book it
would not accept for a moment any gambit, especially long-range
ones like the Benko.

(82) Hodge D. - Hammond T. J. [A35]

East Devon Premier 1999 (3)

1. e4 c5 2.c3 g6 3.d4 cxd4 4.cxd4 d5 5.exd5 Nf6
6.Nf3

6...Bg7

Typically Fritz does not like to be without material, and
prefers 6...Nxd5.

(3) Foulds A. - England M. C. [E76]

Fritz doesn't like giving up Pawns, but this Benko-style idea
looks perfectly legitimate.

[0.94 : 9...b6 10.Qc2 Bb7 11.Be3 Qc7 12.f5 gxf5 13.exf5]

Also, very practical attempts to open or muddle the position are
nearly always criticised. [We need to understand the 'nearly'; it
may be in these positions the compensation is obvious even to a
stupid computer.]

Fritz, like many computers, cannot appreciate positional
sacrifices. These are not easy for club players to contrive except
in certain familiar situations but when they were offered Fritz
poured scorn on nearly all of them.

There is a particular class of move that Fritz always labels a
blunder and with which calumny I cannot agree: the simplifying move
or combination. This may reduce your attacking force, or even give
up some of your material advantage, but still be an excellent
idea.

(7) Price M. C. - Sparkes D. A. [C14]

East Devon Major 1999 (1)

62.Rxe6+ Just the sort of clarifying sacrifice
a human likes and computers hate. In fact, both the Knight and King
are perilously short of squares and can each be profitably
harassed.